Gas tank switching valve plumbing

[Yooper74]

Anyone have a flow path for the under seat valve to switch from main to aux tank?

I'm not quite understanding the 4th line. Some kind of return?

 

[TheLimeRanger]

the stock valve has 3 ports (i think 1973 might be different however) im not sure what the 4th one is for. fuel injection maybe? in the stock setup the left port and right port go to the tanks, and the middle port goes up to the the fuel pump.

 

[SP73]

Not for sure, but it might go to the charcoal canister?

 

[armynavy17]

My guess is it's not a true OE replacement. The center goes to the engine, drivers side to the AUX, and passengers side to the main tank. If you had a third tank you could run one off of the bottom port, otherwise just plug/cap it off.

 

[jckkys]

It's definitely not OE. The Ford valve has all hose connections pointing to the rear not down. The weird '73 valve has 6 nipples so this isn't one of those. Most EBs now have after market valves. It's too bad because the originals are easily rebuilt with a new O-ring made of viton.

 

[Yooper74]

Weird. Was on there when I bought the project so no idea where it came from. Looks fairly new

I’ll block the one port and see what happens